A typical color conversion method converts the colors of all objects included in each page of a document to a single color that provides a feel of consistency to improve the visibility of the objects.
In the typical color conversion method, even if pages in a plurality of different groups are included in a document, the colors of all objects included in each page of the document to a single color that provides a feel of consistency. This makes it hard to differentiate pages in the document for each group, so the content of the document may become difficult for the user to understand.